v0.3.0 specification snapshot

v0.3.0 is the first Agent Runtime snapshot where task is a first-class execution object instead of only a loose background-work label.

Required additions over v0.2.0

A compatible v0.3.0 implementation SHOULD expose:

• task_id and run_id / attempt_id correlation where task execution exists.
• Task lifecycle events from creation through progress, waiting, retry, cancellation, failure, loss, completion, and archive.
• Task graph edges for parent/child, blocks/blocked-by, source task, source attempt, spawned subagent, assigned thread, artifact, and evidence relationships.
• Attempt history that preserves failed runs instead of overwriting task records on retry.
• Task read models in snapshots, including active tasks, blocked tasks, attempts, graph edges, delivery state, and recent terminal tasks.
• Control-plane semantics for create, update, start, progress append, pause, resume, cancel, retry, complete, fail, list, get, link, and unlink tasks.

Key contracts

• Agent task
• Specification
• Runtime model
• Runtime event stream
• State snapshots
• Control plane